A systematic review and meta-analysis «Maher GM, O'Keeffe GW, Kearney PM ym. Association ...»1 reported on the association of maternal hypertension in pregnancy with offspring autism-spectrum disorders (ASD; 20 articles from high-income countries and India, of which 11 with adjusted estimates contributed to meta-analysis), attention deficit hyperactivity disorder (ADHD; 10 articles from high and middle income countries, of which 6 with adjusted estimates). The articles included both case-control and cohort studies, and separate meta-analyses were reported for maternal pre-eclampsia and for "other hypertensive disorder" (mostly gestational hypertension or any hypertension in pregnancy) as exposures.
The pooled unadjusted odds ratio (OR) for ASD for offspring exposed to maternal pre-eclampsia was 1.59 (95 % confidence interval 1.27-1.99) and the OR adjusted for covariates (covariates varied, including maternal age, parity, smoking and educational attainment) was 1.50 (95 % confidence interval 1.26-1.78). For offspring exposed to other maternal hypertensive disorder, the unadjusted OR was 1.40 (95 % confidence interval 1.07-1.82) and adjusted 1.25 (95 % confidence interval 0.90-1.73). For both exposures combined, the unadjusted OR was 1.47 (95 % confidence interval 1.24-1.75) and adjusted 1.35 (95 % confidence interval 1.11-1.54).
For ADHD, the pooled unadjusted odds ratio (OR) for offspring exposed to maternal pre-eclampsia was 1.30 (95 % confidence interval 1.20-1.41) and the adjusted OR adjusted was 1.28 (95 % confidence interval 1.20-1.36). For offspring exposed to other maternal hypertensive disorder, the unadjusted OR was 1.80 (95 % confidence interval 1.15-2.82) and adjusted 1.70 (95 % confidence interval 1.06-2.71). For both exposures combined, the unadjusted OR was 1.31 (95 % confidence interval 1.21-1.42) and adjusted 1.29 (95 % confidence interval 1.22-1.36).
The review included also 31 articles reporting on other neurodevelopmental outcomes. Meta-analysis was not performed. However, some patterns emerged. 6 of 10 studies suggested increased rates of cognitive impairment in offspring exposed to maternal pre-eclampsia, and 4 of 5 studies increased rates of intellectual disability in offspring exposed to other maternal hypertensive disorders.
A systematic review «Tuovinen S, Eriksson JG, Kajantie E ym. Maternal h...»2 evaluated 19 studies (18 in high-income countries, 1 in Brazil) reporting on associations between maternal hypertension in pregnancy and offspring cognitive function. Because of heterogeneity in study design and exposure and outcome definition, no meta-analysis was performed, and the review focused on comparing different types of studies. Of the studies in a general population, 1/4 in children and 2/2 in adults reported statistically significantly less favourable cognitive outcomes (usually lower IQ scores, higher risk of results below a specific threshold, or self-reported impairment) in offspring exposed to maternal pre-eclampsia; 1/1 and 2/2 reported lower cognitive function in offspring exposed to any type of hypertension in pregnancy. Studies in clinic-based populations reported only on childhood cognitive outcomes; 7/10 reported significantly less favourable cognitive outcomes among offspring exposed to maternal pre-eclampsia and 2/7 among offspring exposed to any form of hypertension in pregnancy.
A systematic review and meta-analysis «Dachew BA, Mamun A, Maravilla JC ym. Association b...»3 aimed to assess mental and behavioural disorders in offspring exposed to maternal hypertensive disorders of pregnancy. The meta-analysis included 19 studies, all from high-income countries. Eleven studies reported on schizophrenia as an outcome, with a risk ratio of 1.37 (95% CI 1.08, 1.72). Evidence on other offspring disorder was inconclusive.
A cohort study «Tuovinen S, Räikkönen K, Kajantie E ym. Hypertensi...»4 in the Helsinki 1934-1944 Birth cohort reconstructed diagnoses of hypertensive disorders of pregnancy according to modern criteria, linked these data with the military forces cognitive abilities test performed for men during military service at 20 years, and invited these men for a repeated test at mean age of 68 years. In adjusted analysis, offspring exposed to maternal hypertension in pregnancy had 4.4 IQ points lower cognitive abilities (95 % confidence interval 1.2-7.6) at 68 years and a more rapid decline between 20 and 68 years (mean difference in decline 2.9 IQ points; 95 % confidence interval 0.7-5.1). These differences were virtually similar for the three subscores (visuospatial, arithmetic and verbal).
A cohort study «Barker DJ, Edwards JH. Obstetric complications and...»5 linked obstetric records of all children born in Birmingham, England, between 1950 and 1954, who had attended the verbal reasoning scores of eleven-plus school examination in the city. The scores were reported in units with a mean of 100 and a standard deviation of 15. Much of the conclusions were based on differences between sibships. Children born at term who were exposed to maternal toxemia had 0.7 points lower verbal reasoning score compared to non-exposed siblings in subsequent birth rank and 2.2 points lower score compared to non-exposed siblings in preceding birth rank. The sibling comparisons account for the confounding effects of birth order as toxemia is more common in firstborn children, who also have higher verbal reasoning scores.